Neonatal Lamb Mortality- in Flocks of Merino Ewes Selected for and against Fold Development
ثبت نشده
چکیده
A survey, using reciprocal matings, has been made of neonatal lamb mortality in two Merino flocks, Folds Plus and Folds Minus, which have been selected for and against skin fold development since 1951. Results showed that death of single lambs was concentrated in the group where Folds Plus rams were mated to Folds Plus ewes. This mortality was almost invariably associated with dystocia or difficult birth due to the presentation of over-size lambs.
منابع مشابه
Reproductive performance of commercial Merino, Dohne Merino and SA Mutton Merino flocks in the Southern Cape
Data of 23 189 Merino ewes (8 farms), 7692 Dohne Merino ewes (3 farms) and 2399 SA Mutton Merino ewes (1 farm) were recorded for the 1988-1991 lambing seasons. The udders of ewes present at lamb marking were inspected to differentiate between barren (unlambed), lambed and lost (lambed ewes suckling no progeny), and wet (lambed and suckling ~ 1 lamb) ewes, using the 'wet and dry' technique. The ...
متن کاملThe Influence of Active Immunization Against Adrenocorticotropin Hormone on Galactopoiesis in Merino Ewes
Background:Chronic active adrenocorticotropin hormone (ACTH) immunization of ewes (with a previous history of immunization) resulted in elevated titres of antibody against ACTH, which induced a reduction in circulating levels of cortisol. Objectives:<span style="color: win...
متن کاملManagement of maternal-offspring behavior to improve lamb survival in easy care sheep systems.
This paper examines the environmental and management factors affecting lamb survival on high-performing sheep farms in New Zealand. Improved lambing percentage is the biggest contributor to higher profits on New Zealand sheep farms. Many sheep breeders have selected and bred ewes for increased fecundity over the last 4 decades. The increased proportion of ewes having triplets is of concern to f...
متن کاملEffects of ewe live weight and age on reproductive performance, lamb growth, and survival in Central Anatolian Merino sheep
The aim of this study was to evaluate the effects of premating ewe weight and age on ewe reproductive performance, lamb growth and survival in Central Anatolian Merino (CAM) sheep. The trial included 4935 ewes and 5548 lambs from 23 breeder flocks in Eskişehir Province. The live weights (LWs) and ages of the ewes were recorded 1 week before the mating season. The number of lambs born, fertility...
متن کاملAn Explanation for the Reduced Fertility in Merino Ewes at the First Oestrus of the Breeding Season
Laproscopy was used in 400 ewes from 3 commercial flocks to study the difference in fertility of ewes mated in the first vs. second 2 weeks of the joining period. Examination of the ovaries of the ewes at joining and 14 days after joining revealed that 23% of the ewes did not experience a 'quiet ovulation' at the beginning of their breeding season but ovulated and displayed oestrus simultaneous...
متن کامل